Railway-track circuit



March 3, 1931-. o. s. FIELD 1,794,599

' RAILWAY TRACK CIRCUIT Filed April 20. 1929 Fla. 1.

TTORNEY Patented Mar. 3, 1931 I l I T I r I i UNITED S ATES. PATENT OF C 'i i oscan ,s. FIELD, or noonnsrnn, NEW YORK,-ASSIGNOR TQGENERAL RAILWAY"v SIGNAL comrAnxg-or nocnns'rnn, NEW YORK RAILWAY-TRACK: cmcurr Application filed April 20, 1929. Serial No. ,723.

This invention relates in general to track creases due to the ballast resistanceincreascircuits such as used in railway practice",'and ing, and decreases resistance in therelay cirhas more particular"referencetdmeans for cuit when ballast resistance decreases. In' automatically maintaining the? current this manner, a practically constantcurrent V 5 through a track relay substantially constant flows thorugh the track relay under unoccuregardless of change in ballast resistance; pied conditions of the'block, regardless of In railway operation it is quite essential changes in terminal voltage due to changes in" thatthe usual track relay connected across the ballast resistance. 1 a entrance end, (or exit end) of each signalling Further objects, purposes and character- 10 block be sufficiently energized when the block istic features of the invention will appear as is unoccupied to pick up and holdup with the description progresses, reference being certainty, and at the same timethat occuhad to the accompanying drawing,- showing, pancyof the block will vsoefi'ectively shunt merely by way of example, and in no manner the relay as to cause it to release. These mm in a limiting sense, one form which the in- 15 siderations show that the proper operation of vention can assume. In the drawing a track relay is a marginal affair. For ex- Fig. 1 diagrammatically illustrates one ample, if the normal holding current is too form of the present invention. H hig shunting may not be effective to drop Fig. 2 diagrammatically illustrates a seethe relay, whereas ifnormal holding current 0nd form of the present invention. v, A 2 be placed so low that shunting will with Referring to the drawing, and firstto Fig. greater certainty be effective, it is possible 1, a stretch of single track is shown,consti that at times the holding current maybe intuted by track rails 1 supplied with insulat suflicient. ing joints 2 to form an insulated track seec. Taking the above in consideration, it is tion Av in a usual manner, with a track bat,- I seen that the usual variations in ballastretery 3 and a current limiting resistance 4 sistance encountered in practice, due priconnected across the exit end of the block, 'marily to changes in weather conditions, may (travel being'in the direction of the arrow,) operate to cause improper operation of a and a track relay TR connected across the entrack relay unless some means be provided for trance end of the block. v automatically "compensating for changes in Imbedded inthe ballast between the track 80 ballast resistance. v rails 1 is a groundconnection 5 which may As the ballast resistance increases, the balbea section of rail or the like. A control batlast leakage, or the flow of current between tery CB has one terminal connected to this the rails, decreases, so that the voltage across ground connection, and the other. terminal 3 the terminals of a track relay connected in connected to the winding of a control relay such a circuit increases. Conversely, as the CR, the other end 01 the winding of CR beballast resistance decreases, ballast leakage ing connected to one of the track rails 1. The increases and the terminal voltage at the rerelay CR has an armature 6 pivoted at 7, and lay decreases; Unless provision be; made controlling the pressure exertedon a carbon 40 for regulating the current flowing through pile GP which is inserted in the energizing therelay, this current will vary overaconsidcircuit of the track relay TR, whereby to erable range, and very possibly cover a range vary the resistance of the track relay enersuflicient to at times prevent proper operagizing circuit.

tion of the relay under occupied or unoccu- As set forth above in the introductory por- 4 pied conditions of its block. tion of this specification, as the ballast resist- .95

' It is proposed, in accordance with thisinance increases, the voltage applied a'cross'the Vention, to provide means in series with a track relay at its connection to thetrack rails track relay which automatically increases the increases, and tends to increase the normal resistance in the energizing circuit for the holding current through the relay, to possi- 5 track relay when its terminal voltage in ly increase it so greatly as to prevent proper shunting actionupon occupancy of its block. The increase in the ballast resistance howdecreases, but the regulating means increases pressure on the carbon pile to decrease resistancein the track relay circuit sutficiently to maintain the track relay current substantialulating means. v

trol means can be employed in this connec- ,tion, and the invention contemplates such use.

ly constant.

' The various lnstrumentahties employed 1n the shown embodiment of this invention, and

described above, are of course only illustrative, and can be replaced by variousother reg Electron tubes, or other con- Also', armature 6 can be spring biased in either clockwise or counter-clockwise direction, or both, if desired. Also, ground connection 5 can be comprised of a plurality of members variously embedded in the ballast, both as regards depth and position laterally relatively tothe track rails.

It' shouldbe noted that occupancyoi the block does'not shunt the electro-magnet-or control relay GR and hence does not materially affect the automatic control, as is the case in the Howe application (Ser. No. 356,716) filed of even date herewith, and entitled .Track circuits. 7 In this form of invention, however, occupancy does connect up the tworails by a. very low resistance connection, so as to supply two multiple paths, instead of the normal single path, for flow 0. current from batteryv CB, from 5 to the left lead of relay CR, and thus affects the auto matic' control to a slight extent. Accordingly, unless very accurate control is required, there is no great occasion in this invention, to provide slow acting, or retarding, means in the control, as is provided in the Howe invention referred tojust above.

The arrangement in Fig. 2, is the same as Fig. 1, except a double wound relay CR used, each connected at one end to 5 and-at the other ends, connected respectively, to the two track rails 1, as shown. With this form, there is already, in normal unoccupied condition of the track section, two mutiple paths from 5 through the relay CR Thus,a shunting car cannot affect the automatic control to I any appreciable extent.

. cupancy of its block,and a decrease in'ballast resistance cannot under energize the track relay so as to cause it to release when .not shunted out due to occupancy of its block.

The above rather specific description of one form of the present invention has been'g'iven solely by way of illustration, and is not .in--

tended, in any mannerwhatsoever, in a limitingsense. Obviously, this invent on can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications are .inc'ludedby this application, as come within the scope of the appended claims.

Having described my invention, I claim: I a

: 1 ..In a track circuit, in combination with an insulated stretch of track, a source of elecnow ,trical energy connected'a-cross one endiof the track, and a track relay connected across the.

sponsive to changes inballast resistance, and" independent of the track circuit.

2. In a track circuit, in combination'with aninsulated stretch of track, a source of electrical energy connected across one end of the track,-and a track relay connected across the.

llO

ing the resistance to current flow through the track relay according as the ballast resistance increases or decreases, respectively, said regulating means including, a carbon pile resistance, a control relay having one terminal connected to a track rail, a ground member buried in the track ballast adjacent the track rails, and a source of electrical energy 'connected between another terminal of the control relay and the ground'member.

3.. In a track circuit, in combination with an insulated stretch of track, a source of electrical energyconnected across one end of the track, and a track relay connected across the other end of the track; regulating means for automatically maintaining the normal energizing current through the track relay substantially constant regardless of variations in ballast resistance, by increasing or decreasing the resistance to current flow through the track relay according as the ballast resistance increases or decreases, respectively, said regulating means including a double wound control relay having one terminal of each winding connected to respectively each track rail, a ground member buried in the track ballast adjacent the track rails, and a source of electrical energy connected bet-ween the ground member and a terminal common to the two windings of the control relay. y i

4. In a track circuit, in combination with an insulated stretch of track, a source of electrical energy connected across one end of the track, and a. track relay connected across the other end of the track; regulating means for automatically maintaining the normal energizingcurrent' through the track relay'substantially constant regardless of variations in ballast resistance, by increasing or decreasing the resistance to current flow through the track relay according as the ballast resistance 7 increases or decreases, respectively, sald regulating means including a double wound control relay having one terminal of each winding connected to respectively each track rail, a ground member buried in the trackballast adjacent the track rails, and a source of electrical energy connected between theground member and a terminal common to the two windings of the control relay, the two windings of the control relay being connected to said source of electrical energy so that their energized effect due to said source of electrical energy, is cumulative.

5. In a track circuit, in combination with an insulated stretch of track, a source of electrical energy connected across one end of the track, and a track relay connected across the other end of the track; regulating means for automatically maintaining the normal energizing current through the track relay substantially constant regardless of variations in ballast resistance, by increasing or decreasing the resistance to current flow through the track relay according as the ballast resistance increases or decreases, respectively, said regefl'ect of the said two windings, dueto the track battery, is opposing. a

6. In a track circuit, in combination with an insulated stretch of track, a source of electrical energy connected across one end of the track, and a track relay connected across the other end of the track; regulating means for automatically maintaining the normal e'nerf gizing current through the track relay substantlally constant regardless of variations in ballast resistance, by varying theresistance to current fiow through the track relay according as the ballast resistance varies, said regulating means including a doublewound control relay having one terminal of each winding connected respectively to each track rail and a source of electrical energy connected between the ground and a terminal common to the two windings of the control relay.

' In testimony whereof I aflix my signature. 7

OSCAR s. FIELD.

ulating means including a double wound control relay having one terminal of each winding connected to respectively each track rail, a ground member buried in the track ballast adjacent the track rails, anda source of electrical energy connected between the ground member and a terminal common to the two windings of the control relay, the two windings of the control relay being connected to said source of electrical energy so that their energized effect due to said source of electrical energy, is cumulative, and the energized 

